[Haskell-cafe] Toy compression algorithms [was: A very edgy language]

Stefan O'Rear stefanor at cox.net
Sun Jul 8 11:22:03 EDT 2007

On Sun, Jul 08, 2007 at 04:07:59PM +0100, Andrew Coppin wrote:
> The way I heard it is that it *does* native code generation, but it's "not 
> as good" as the via-C version. (Can't imagine why... You would have thought 
> directly implementing functional primitives would be much easier than 
> trying to mangle them to fit C's multitude of limitations. Still, what do I 
> know?)

This is very true - but -fvia-C isn't really C.  First it generates GCC
C (with global register variables, among other things), then it feeds
the output through gcc - and then it runs a GHC-specific Perl script
called the Evil Mangler over the assembly output, which promptly regexes
your code to death.

If you want to see what a difference exists between true C and the NCG,
try compiling your program with -fvia-C -unreg.  -unreg tells GHC to
generate (something very close to) ANSI C; also, the mangler is not
used.  -unreg is mainly used for porting...


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